Aryl guanamines



Patente d Sept. 9, 194? use-es STATES PATENT 'i/OFFICE carboxylic acid I is" so" active that it willieact with p or phenols; for the fgij'i ifiir' iev I .J JackzTheo Thurston flos Cob, Conn, assignor to I --American- Cyanamid Company, New .York-, ;N.,;Y.,a.corporation,of Maine:

Y 'Nonmwf n'g. "Application August 3011941,; Sria No.409, 12 ,1i i.

.-(o1.2eo -249.5

the esters of low-molecular weightmonohydric paraffin alcohols. These; esters. are highly re active;-give good yields, are cheap, and present the additional advantage that when an ester is i i employed, the alcohol group of. ,whichis the same the bi'guanide in the cold "or -without being "heated toanyvery high temperature to givethe-correspending guanamine in good yield, and it is an advantageof thepresent invention that'many'of tuted' aryl' guanamines; the reaction-"ofthe corre' sponding substituted biguanide. 'withzan ester of theamm'atic carb'oxylic acid issomew-hat too slow for practical use, and in such cases the reaction canbe-acce1erated-by the use 'of a strong base;

such asa metal alkoxide;'rnetal amidefor sim ilar compounds capable of reacting with an alcohol to produce'an alkoxide.' 1

action of the present? invention 1 in solution -and for-this pur ose alcohols are the preferred solvents, especially the lower rnonohydric paraffin alcohols such'as'methan'ol' and"ethanol. These alcohols .are a good solvents.- for 1 biguanide; .andgfor 1 Ingeneral,--it"isdesirable to car'ry out there the 'arylguanamines*can'thus be prepared-simply. Howeverpin' some casesi'notably'with N;-substi-'-' as the alcohol used as the solvent, no additional recovery problem is presented. For this reason I prefer to use thelovvermonohvdric alcohol esters, although the invention is not limited thereto, as

other esters, even polyhydric esters, can be used.

The inventionwill be described in greater detail in conjunction with the following specific examples, which are typical illustrations of the invention. The parts are by weight.

" l naphtho'guanamine Eighteen parts of biguanide were dissolved in 80 parts of methanol, the solution was filtered, and 25 parts of ethyl l-naphthoate added. After standing overnight, the guanamine: had commost of the substituted biguani'deaandthey. ap-.

pear also to have some iniluenceon the reaction. While the invention is not limited to the use of any particular alcohol as a solvent, I find that methanol gives excellent results, as does ethanol, and in some cases, theethyl' ether ofethylene glycol: For this reasonand'bec'ause of itscheapness, ready availability'and easy recovery, methanol is the preferredsolvent. V r

The aromatic carbo iylic acid may be one in which the carboxyl group is 5 attached to "a'niiclear carbon atom, or the carboxyl group may be present in a chain such as, for example, cinnamic acid or phenyl acetic acid. The esters of the nuclear carboxylic acids are, in general more reactive.

The particular ester of the carboxylic acid is not critical. In general, the reaction can be made to go with esters of any of the ordinary alcohols pletely precipitated and was removed by filtration and recrystallized from a mixture of of the tliyl 'ether of ethylene glycol 'and-10%= water. The :yi'eld of the prod'u'ctin :thel form'of small colorless-needles melting'at 276 C.-, was about V, A j3hvdro1iY-?-naphtlioguanainine HiN-C j l I I One hundred and forty parts of biguanide were dissolved in about 1500 parts of methanol and 304 parts of methyl 3-hydroxy-2-naphthoate were added, and the solution filtered. The guanamine began to precipitate within an hour and after standing overnight it was removed by filtration and recrystallized from hot n-butanol. The yield most; part I prefer to use.-

3 of product, which was in the form of bright canary yellow needles melting at 317 C., was about 70%.

Example 3 i-N'-al1ylbenzoguanamine 0. l i H2N-C CNHCH2CH=CH2 N To 38 parts of allylbiguan-ide dissolved in- 200' parts of methanol containing 6.5 parts of sodium metal was added 53.2 parts of methyl benzoate. After standing about two hours, the product began to precipitate and on further standing the reaction mixture set to a gelatinous solid. An equal volume of water was added and the product was cooled, in an ice-bath; in order to obtain compl-ete crystallization. The -N-allylbenzoguanamine was filtered from solvent, washed with water and then dried. The yield of crude product melting at 1149-116 0. was almost quantitative and after recrystallization from alcohol it melted at 1l5-1l6 C.

Example 4 i-N-phenyl-benzoguanamine 88.5 parts of phenylbiguani'de dissolved in 200 parts of methanol containing 11.5 parts of sodium were mixed with 125 parts of methyl benzoate. Precipitation started within 15 minutes and was substantially completein 214 hours. After recrystallization from toluene, 4-N-phenyl benzoguanamine was obtained having a melting point of 199-201 C., the yield being about 37%.

Ewample 5;

Z-hydroxycinnamoguanamine 21.2 parts of biguanide were; dissolved in 100 parts of methyl alcohol, the solution was filtered and then a solutionof 29.2v parts of coumarin dissolved in 80 parts of methyl alcohol were added. Reaction took place slowly and was speeded up by the addition of a small amount of sodium methoxide. The solution was acidified with acetic acid and evaporated, giving a yellow solid which was boiled with water, filtered, and finally dissolved in the ethyl ether of ethylene glycol. On dilution with an equal volume of naphtha, fine light yellow needles, melting at 296 C., were precipitated. The yield was about 4 Example 6 l-N-p-oxydiethylene-bcnzoguanamine N CHr-CH:

40 parts of N-biguanylmorpholine hydrochloride were mixed with 34 parts of methyl benzoate, using 1Q.'l parts of sodium in 200 parts of methanol both as a condensing and neutralizing agent. The sodium chloride formed in the neutralization of the N-biguanylmorpholine hydrochloride was filtered off and the filtrate allowed to stand for about a day. Gradual solidification took place. The small amount of liquid remaining was filtered off, producing about 56 parts of solid which was slurried with parts of boiling water, then cooled to 2025 C. and filtered. The product obtained melted at 142-143 C.

Emample 7 Phenylacetoguanamine Ii-C1120 V N N A N HgN- c-Nm To 24 parts of, biguanide dissolved in parts of methanol was; added 45 parts of ethyl phenylacetate. Product began to precipitate. immediately and within an hour the reaction appeared to be complete. The product was removed; by filtration and the yield of. phenylacetoguanamine melting at 232-233."- C. was. 80%. After recrystallization from hot ethyl acetate and then from the ethyl. ether of ethylene glycol, the purifiedv phenylacetoguanamine. melted at 237-.238 C.

What I claim is:

1. A method of preparing a guanamine which comprises. reacting a biguani'de with an ester of an aromatic carboxylic acid in the presence of a. metal alkoxide in stoichiometric proportions.

2. A method of preparing a uanamine which comprises reacting biguanide, with an ester of aromatic carboxylic acid in the presence of a metal alkoxide. in stoichiometric proportions.

JACK TI-IEO THURS'ION.

RE ER NCES GI ED The following references are of record in the file of this patent:

UNITED STATES PATENTS.

OTHER REFERENCES Berichte de D. Ch m Gest. vol; 25-, pp. 361 Annalen, vol. 376-, pp. 1:80 and 1,81,. 

